Method of operating blast furnaces



Patented Dec. 9, 1924.

UNITED STATES PATENT OFFICE.

METHOD OF OPERATING BLAST FURNACES.

No Drawing.

T 0 all whom it may concern:

Be it known that I, EDMUND B. KIRBY, a

citizen of the United. States, residin at New York city, in the county of New ork and State of New York, have inventeda certain new and useful Improvement in Methods of Operating Blast Furnaces, of which the following is a full, clear, and exact description.

The present invention relates to a method of operating blast furnaces and 1s applicable generally wherever blasts of oxygen or air enriched with oxygen are m ected into a furnace containing the material to he treated and solid fuel.

In my patent application 358,9 69, filed February 16, 1920, I have described 1mprovements in the operation of blast furnaces which involved the use of a blast of oxygen or air enriched with oxygen and which also permit the use, when desired, of injectable fuel such as fluid fuel or powdered fuel. I have invented further methods 1n the details of applying these improvements as follows:

In order to aid in protecting the tuyeres from the high and quick temperatures developed by a blast of oxygen or an enriched with oxygen, particularlywhen powdered fuel or liquid fuel are in ected, 1t 1s preferred to introduce steam in or near the blast.

The quantity of steam is made sufliclent to cool the fuel first encountered by the oxy en at the tuyere nozzle, the effect being to elay the heat generation until the our rent has passed away from the tuyere and thus to protect it and also to protect the injection apparatus for the powdered fuel or liquid fuel when such apparatus 1s present. l/Vhen using such fuels moreover, I prefer to employ a jet of steam as the best means of injecting them.

To make the protection most effective, the exposed parts of the tuyeres should be in contact with the steam and not with the oxygen and any convenient arrangement for effecting this is desirable. For instance, the steam jet which carries the fuel may be of annular form surrounding the jet of oxygen or an additional jet or current of steam may be made toform a protective barrier between the exposed parts and the oxygen. I do not restrict myself to any particular Application filed August 6, 1920. Serial No. 401,751.

arrangement or to any form of tuyere and in ection apparatus as a large variety of these are known in the art.

Even where metal surfaces are not exposed but refractory materials are used, it will still be of advantage to protect them by utilizing the steam in the above manner.

It may be ex lained that the injectable fuels to which refer constitute a wellunderstood and clearly defined class distinguished by having the peculiar qualities necessary for combustion within the interstices of a blast furnace column.

Such fuel to he injected must either be gaseous or be liquid or be a solid powdered finely. They must thus be capable of bein scattered by the injection force into liquid globules or solid particles, which are small enough to be carried by the injection current through the fine interstices of a blast furnace column and to mix with the blast and to be consumed quickly by virtue of their small size, before choking these interstices.

For convenience, therefore, I shall refer to all such fuels as injectable fuel.

Having described my invention, I claim:

1. The method of operating a blast furnace which consists in supplying it with the material to be treated and solid fuel also a blast of steam and oxygen or air enriched with oxygen.

2. The method of operatin a blast furnace which consists in supp ying it with the material to be treated and solid fuel also a blast of steam and oxygen or air enriched with oxygen, the steam or a part of it being so introduced as to occupy the space between the oxygen and the exposed parts of the tuyeres.

3. The method of operatin a blast furnace which consists in supp ying it with the material to be treated and injecting steam, injectable fuel and oxygen or air enriched with oxygen.

4. The method of operating a furnace which consists in supplying it with the material to be treated and injecting steam, in-

jectable fuel and oxygen or air enriched with oxygen.

5. The method of operating a furnace which consists in supplying the material to be treated and injecting powdered or injectable fuel, steam and oxygen or air en- 'riched with oxygen,

the steam or a part of it being sol introduced as to occupy the space between the oxygen and the exposed I parts of the injection apparatus.

6. The method of operating a furnace which consists in supplying the material to be treated and injecting injectable fuel, oxygen or air enriched with oxygen and a protecinert to said present.

. The method of operating a furnace which consists in supplying the material to be treated and solid fuel and injecting an injectable fuel, steam and oxygen or air enriched with oxygen into the interstices of a mass of incandescent solid fuel.

In testimony whereof, I hereunto affix my signature.

parts and also to the oxygen EDMUND B. K'IRBY. 

